Remove createImageData() fallback

All our browsers should be new enough now that we can rely on the
ImageData constructor.

core/display.js

@@ -8,7 +8,6 @@
 
 import * as Log from './util/logging.js';
 import Base64 from "./base64.js";
-import { supportsImageMetadata } from './util/browser.js';
 import { toSigned32bit } from './util/int.js';
 
 export default class Display {
@@ -56,11 +55,6 @@ export default class Display {
 
         Log.Debug("User Agent: " + navigator.userAgent);
 
-        // Check canvas features
-        if (!('createImageData' in this._drawCtx)) {
-            throw new Error("Canvas does not support createImageData");
-        }
-
         Log.Debug("<< Display.constructor");
 
         // ===== PROPERTIES =====
@@ -393,13 +387,7 @@ export default class Display {
             let data = new Uint8ClampedArray(arr.buffer,
                                              arr.byteOffset + offset,
                                              width * height * 4);
-            let img;
+            let img = new ImageData(data, width, height);
-            if (supportsImageMetadata) {
-                img = new ImageData(data, width, height);
-            } else {
-                img = this._drawCtx.createImageData(width, height);
-                img.data.set(data);
-            }
             this._drawCtx.putImageData(img, x, y);
             this._damage(x, y, width, height);
         }

core/util/browser.js

@@ -45,15 +45,6 @@ try {
 
 export const supportsCursorURIs = _supportsCursorURIs;
 
-let _supportsImageMetadata = false;
-try {
-    new ImageData(new Uint8ClampedArray(4), 1, 1);
-    _supportsImageMetadata = true;
-} catch (ex) {
-    // ignore failure
-}
-export const supportsImageMetadata = _supportsImageMetadata;
-
 let _hasScrollbarGutter = true;
 try {
     // Create invisible container

core/util/cursor.js

@@ -87,14 +87,7 @@ export default class Cursor {
         this._canvas.width = w;
         this._canvas.height = h;
 
-        let img;
+        let img = new ImageData(new Uint8ClampedArray(rgba), w, h);
-        try {
-            // IE doesn't support this
-            img = new ImageData(new Uint8ClampedArray(rgba), w, h);
-        } catch (ex) {
-            img = ctx.createImageData(w, h);
-            img.data.set(new Uint8ClampedArray(rgba));
-        }
         ctx.clearRect(0, 0, w, h);
         ctx.putImageData(img, 0, 0);
 

tests/test.display.js

@@ -4,28 +4,27 @@ import Base64 from '../core/base64.js';
 import Display from '../core/display.js';
 
 describe('Display/Canvas Helper', function () {
-    const checkedData = new Uint8Array([
+    const checkedData = new Uint8ClampedArray([
         0x00, 0x00, 0xff, 255, 0x00, 0x00, 0xff, 255, 0x00, 0xff, 0x00, 255, 0x00, 0xff, 0x00, 255,
         0x00, 0x00, 0xff, 255, 0x00, 0x00, 0xff, 255, 0x00, 0xff, 0x00, 255, 0x00, 0xff, 0x00, 255,
         0x00, 0xff, 0x00, 255, 0x00, 0xff, 0x00, 255, 0x00, 0x00, 0xff, 255, 0x00, 0x00, 0xff, 255,
         0x00, 0xff, 0x00, 255, 0x00, 0xff, 0x00, 255, 0x00, 0x00, 0xff, 255, 0x00, 0x00, 0xff, 255
     ]);
 
-    const basicData = new Uint8Array([0xff, 0x00, 0x00, 255, 0x00, 0xff, 0x00, 255, 0x00, 0x00, 0xff, 255, 0xff, 0xff, 0xff, 255]);
+    const basicData = new Uint8ClampedArray([0xff, 0x00, 0x00, 255, 0x00, 0xff, 0x00, 255, 0x00, 0x00, 0xff, 255, 0xff, 0xff, 0xff, 255]);
 
-    function makeImageCanvas(inputData) {
+    function makeImageCanvas(inputData, width, height) {
         const canvas = document.createElement('canvas');
-        canvas.width = 4;
+        canvas.width = width;
-        canvas.height = 4;
+        canvas.height = height;
         const ctx = canvas.getContext('2d');
-        const data = ctx.createImageData(4, 4);
+        const data = new ImageData(inputData, width, height);
-        for (let i = 0; i < checkedData.length; i++) { data.data[i] = inputData[i]; }
         ctx.putImageData(data, 0, 0);
         return canvas;
     }
 
-    function makeImagePng(inputData) {
+    function makeImagePng(inputData, width, height) {
-        const canvas = makeImageCanvas(inputData);
+        const canvas = makeImageCanvas(inputData, width, height);
         const url = canvas.toDataURL();
         const data = url.split(",")[1];
         return Base64.decode(data);
@@ -44,7 +43,7 @@ describe('Display/Canvas Helper', function () {
         it('should take viewport location into consideration when drawing images', function () {
             display.resize(4, 4);
             display.viewportChangeSize(2, 2);
-            display.drawImage(makeImageCanvas(basicData), 1, 1);
+            display.drawImage(makeImageCanvas(basicData, 4, 1), 1, 1);
             display.flip();
 
             const expected = new Uint8Array(16);
@@ -300,7 +299,7 @@ describe('Display/Canvas Helper', function () {
         });
 
         it('should support drawing images via #imageRect', function (done) {
-            display.imageRect(0, 0, 4, 4, "image/png", makeImagePng(checkedData));
+            display.imageRect(0, 0, 4, 4, "image/png", makeImagePng(checkedData, 4, 4));
             display.flip();
             display.onflush = () => {
                 expect(display).to.have.displayed(checkedData);
@@ -316,7 +315,7 @@ describe('Display/Canvas Helper', function () {
         });
 
         it('should support drawing an image object via #drawImage', function () {
-            const img = makeImageCanvas(checkedData);
+            const img = makeImageCanvas(checkedData, 4, 4);
             display.drawImage(img, 0, 0);
             display.flip();
             expect(display).to.have.displayed(checkedData);